Things You'll Need
Petunias bloom in a range of colors, producing large blossoms nestled inside low-growing foliage. As an annual flower, petunias must be replanted in the garden each year, which requires the purchase of fresh seed or new seedlings. Save money and continue to grow your favorite petunia varieties each summer by saving seed from your existing plant. Each petunia flowers produce many small seeds, so you only need to save seeds from three or four plants to have enough to plant your garden next year.
Inspect the petunia plants after the flowers have faded and the petals begin to fall off. Locate the seed pod, which is an oblong, swollen pod produced where the flower was located. Immature pods are green in color.
Cut the seed pod from the plant with shears once it turns tan or brown, but before the pod begins to split open. Place the pod in paper bag, which catches any seed that may fall out from the pod.
Set the bag in a warm, well-ventilated room for seven to 10 days so the pods can finish drying. Leave the bag open to allow air circulation around the pods.
Hold the pods over a bowl and split them open with your fingernail. Shake the seeds out of the pod and into the bowl, separating any plant material from the seeds.
Place the seeds in an envelope labeled with the petunia variety or color and the harvest year. Seal the envelope closed and store it in a cool, dark place until you are ready to plant the seeds.
Harvest seed from more than one plant. If one plant produces unviable or inferior seed, you'll have backup seeds available.
Do not save seed from hybrid petunia varieties, as these will not produce plants that look like the parent.